Teletypewriter switching system



Jan. 6, 1942. o. MOD. PATTON TELETYPEWRITER SWITCHING SYSTEM Filed June 9, 1939 6 Sheets-Sheet l FIG. 2

INVEN TOR 0. M. PA 7' TON 0M fr/ Q5042 A T TOR/V5 V o. M D. PATTON 2,269,379 TELETYPEWRITER SWITCHING SYSTEM Filed June 9, 1959 6 Sheets-Sheet 2 Jan. .6, 1942. I

/N VE N TOR 0J4. PA TTON A TTORNE 1 "BY W tho mm $30528 m MM QEEEEQ mm P U wmvk oo o 9;

1942. o. McD. PATTON 2,269,379

TELETYPEWRITER SWITCHING SYSTEM Filed June 9, 1939 6 Sheets-Sheet I5 /N VE N TOR QM PATTON l'l H N9 w: w

T OBNLY \vqw E s Sheds-Sheet 4 IN VE NTOR 0 M PATTON O. M D. PATTON Fi1ed June 9, 1939 TELETYPEWRITER SWITCHING SYSTEM Jan. 6, 1942.

A T TORNQ V 'Jan. 6, 1942- 0. mo. PATTON 2,269,379

TELETYPEWRIT ER SWITCHING SYSTEM Filed June 9, 1939 6 Sheets-Sheet 5 ATTORMEY QNn .5 Rm

0 wbizou w Rn 33358 0 0 was 3 0 uni a GI .v.

Jan. 6, 1942. o. MCD. PATTON TELETYPEWRITER SWITCHING SYSTEM Filed June a} 1,939 e Sheets-Sheet s .II- Ill-L n 8.0 ZOE-Ru "5 a til [1; I-&

wvsuron By 0. M PATTO/V ili QQm EOR vkm .liL

GOV 20R VKM ATTORNEY Patented Jan. 6, 1942 rawrrrcwnrran swrrcnmo srs'raM Oscar McDonald Patton, Philadelphia, Pa.,' asslgnor to American Telephone and Telegraph Company, a corporation of New York Application June 9, 1939, Serial No. 278,348

41 Claims.

This invention relates to a teletypewriter switching system and, more particularly, to a teletypewriter switching system employing instrumentalities mounted upon the movable type basket carriage of a page printing telegraph machine for controlling the switching of communication lines in a printing telegraph system.

Heretofore, the mechanical or automatic switching of lines in a printing telegraph system has been controlled chiefly by contacts mounted upon stationary parts in a tape printing telegraph machine, such as the contacts shown in Patent 2,120,235, granted June 14, 1938, to J. F. Beattie et al. The switching apparatus shown in this Beattie et al. patent is shown to be mounted principally upon a stationary type basket.

Accordingly, it is an object of this invention to employ a page printing telegraph machine for operating control contacts.

Another object of this invention is to provide a teletypewriter having a movable type basket carriage with improved means for mechanically, or automatically, controlling the switching of telegraph lines.

It is also an object of the invention to provide a teletypewriter having a movable type basket carriage with switching contacts for controlling the switching of telegraph lines and improved means for causing a switching operation to be efiective only when the type basket is in a preassigned position.

A further object of the invention is to mount I switching contacts upon the movable type basket carriage of a teletypewriter and to connect them to their switching circuits by means of slip connector fingers.

These objects of the invention are attained by mounting a plurality of pullbar contacts, of the type shown in the Beattie et a1; patent, the disclosure of which is incorporated herein by reference as a part of this specification, upon a contact yoke in a teletypewriter having a movable type basket carriage. These contacts are connected by conductors to a set of slip connector fingers aflixed to the movable type basket. Another set of slip connector fingers is mounted on a stationary bracket in the teletypewriter and is designed to engage with the other set of fingers only when the type basket is in its return position. When the type basket moves away from its return position, it carries with it one set of fingers thereby opening the circuits through the fingers. Consequently, the operation of the pullbar contacts is effective to accomplish the switching functions only when the type basket is in its return position. 7

Switching operations are performed by preceding each message with a carriage return signal and a particular preassigned permutation code signal which meets the closing of a selected pullbar contact thereby closing a switching circuit through the slip fingers to energize a switching relay which operates and locks-up to connect the desired station to the calling station. When the switching operation has been performed, it remains in efiect until a preassigned signal is transmitted over the system to unlock the selected switching relay which, in releasing its armatures, restores the system to its normally unoperated condition.

A modification of the invention is designed to enable an operator at a main transmitting teletypewriter station to either transmit a message to a selected teletypewriter station or else broadcast a message simultaneously to a selected plurality of the teletypewriter stations in the system by eilecting operation of switching apparatus under the control of slip connector fingers in the teletypewriter at the main oflice.

Another modification of the invention permits an operator at a main transmitting station to select, by means of slip connector fingers and their associated apparatus, any one of a plurality of communication channels. Each channel has several subscribers stations connected therein and means are provided for enabling an operator at the main station to effect the operation of slip connector fingers and pullbar contac s in the teletypewriters at the subscribers stations to condition these stations in such a manner that the message signals transmitted over the selected line will be recorded by only one subscriber's station to the exclusion of the other subscribers stations in the selected channel. Further broadcasting means allow the operator at the main station to select more than one of the communication channels for the simultaneous transmission of message signals thereover which will be recorded practically simultaneously by either a selected station on each of the selected channels or by all of the stations on the selected channels.

These and other features of the invention will be more fully described in detail in connection with the following detailed description of the drawings, in which:

Figure 1 is a front view of a teletypewriter having a movable type basket carriage on which is mounted, a contact yoke carrying a plurality of pullbar contacts connected to a set of slip conbasket showing it to .be in its retumposition and showing the sets of slip connector fingers to be in mutual engagement; Q g Y 3 Fig. 3 is a simplified view taken along the line 3-3 in Fig. 2 and illustrates the manner in which a pullbar contact is mounted-for operation by a.

pullbar;

Fig. 4 represents the manner in which a pair of slip connector fingers are held in mutual engagement; v v

Fig. 5 is taken along the line 5-5 in Fig. 2,

omitting the pullbar contacts for the, sake ofsimplicity, and shows the manner in which the contact yoke is mounted upon the frame of the type basket;

Fig. 6 is a circuit diagram of the selective switching system as a whole showing the pullbar contacts and slip fingers schematically;

Fig. 7 is a modification of the selective switching system in which instrumentalities have been provided to enable a control printer to either transmit a message to a selected printer or else broadcast a message simultaneously to a selected plurality of the outlying teletypewriters;'

Fig. 8 illustrates a circuit which is somewhat similar to the system shown in Fig. '7 except that it employs electrically operated means instead of manually operated instrumentalities for assisting in selecting a plurality of the subscribers stations for connection into a broadcasting'circuit;

Fig. 9 represents the main teletypewriter transmitting station in a selective switching system having a plurality of communication channels extending therefrom with apparatus at the main station for enabling the operator to select any To perform a printing operation, the selected code bars 60 are operated to allow the proper pullbar 63 to fall into the aligned notches of code bars 60 where it is urged outwardly by the pullbar bail with the result that its associatedv type bar 61 is driven upward to strike against the inking ribbon 59 and the platen I I.

Mounted just in front of studs 6| and 82 is a contact yoke III on which are mounted a plurality of spring contacts II, l3, l3, I4 and I5. As is shown inFig's. 1, 2 and 5, contact yoke I is bolted to a pair of brackets -5 which are secured'to the type bar carriage frame 5| by the same bolts I! which fasten the bell crank mounting plate 49 to frame 5|. The manner in which the spring contacts l2, l3, II and I5 are mounted for operation by the pullbars G3 is illustrated in Figs.

- 1, 2. and 3, but more particularly in Fig. 3 which shows a contact I with its component parts appropriately spaced apart and bolted to the contact yoke l0. As is shown in Fig. 3, the set of spring contact points of contact I4 are normally channel and any outlying teletypewriter station on the channel for communicative purposes or to broadcast over a plurality of the channelsto a plurality of the subscribers stations; and

Fig. 10 illustrates the selective conditioning apparatus at several of the subscribers teletypewriter stations connected into a communication channel extending to the main station shown in Fig. 9. I

The printer type of mechanism shown in Fig. 1 is a page printing telegraph machine of the type described in Patent 1,904,164 granted April 18, 1933, to S. Morton et al. The disclosure of this Morton et a1. patent is incorporated herein by reference as a part of this specification. As is described in the Morton et al. patent, the teletypewriter includes a base unit I, a printing unit 2, a type bar carriage unit 3, a stationary platen unit 4, and a manually-operated keyboard unit 6. The type barcarriage unit 3 is provided with rollers 20| and 202 slidably mounted on rail I91 and has another roller (not shown) slidably mounted on rail I98. During the printing of a line, operating means cause the type basket 3 to be moved, step by step, alongrails I91 and H18 in a fixed path of travel from left to right. When a full line has been printed or when it is desired to return the type carriage 3 to the left to commence a new line, means are provided whereby the type carriage 3 can be moved to its return position either in re ponse to the transmission of a preassigned permutation code combination or by the manual operation of the carriage release held open, as are contacts ll, l2 Hi and I5, by the insulated tip 8 of its extension arm which is in engagement with, or which rests upon, the top edge of a pullbar 63 at a point near the end of the pullbar 63.

When this particular pullbar 63 is selected by the aligned notches in code bars 60, it drops down to its selected position in the bottom of the notches. Tip 8 follows pullbar 63 in a downward movement which is of sufiicient extent to allow the set of spring contact points of contact I to close since the force of the spring tends to close them. Contact I 4 remains closed until the pull- I baroperating bail has completed-its cycle of operations at which time it lifts the pullbar 63 up off thecode bars to its unselected position thereby opening the contact points of contact M. The other pullbar'contacts ll, I2, l3 and I5, are operated in a similar manner and constitute what may be termed amechanically operated switchboard. A movable contact mounting bracket 20 is suitably secured tothe bell crank retaining bar 53,

the bell crank mounting plate 49, and to the type bar carriage frame 5|. Attached to bracket 20 are a plurality ofslip connector fingers 2|" to 28,

' inclusive (shown schematically in Fig. 6). Fixfingers in Fig. 2; but, when the type basket 3 is moved to the right, as is shown in Fig. 1, the slip fingers lever as is explained in the Morton et al. patent. 76

edly secured to the left portion of base I is a stationary contact mounting bracket 30 on which another set of slip connector fingers 3| to 38, inclusive (also shown schematically in Fig. 6) is mounted for engagement with the other set of slip fingers 2| to'28.

The manner in which these slip fingers engage is illustrated in Fig. 4 which shows that the end of one finger 2| in the set of fingers mounted on bracket 20 is bent in one direction whereas the end of a finger 3| in the set mounted on bracket 30 is bent in the opposite direction.

Thus, when the type carriage 3 is moved to the left to its return position, the two sets of slip will engage with each other, as is shown mounted -on bracket 30 will be carried with it and will be taken out of engagement with the fingers mounted on the stationary bracket 30.

The slip fingers on the movable bracket 20 are wired tothe pullbar contacts II, II, |3, l4, and I5 and the fingers on the stationary bracket 3|! are wired to a plurality of switching relays as shown in Fig. 6. Consequently, when the type carriage 3 is in its return position, the twosets of fingers prepare circuits'for controlling the switching relays.

When one of the pullbar contacts l2, l3, l4, and I is now closed, it completes a circuit to one of the switching relays. Then, when the type carriage 3 is moved to the right in response to a letter spacing operation, the slip fingers on the bracket are also carried to the right and are taken out of engagement with the fingers on the bracket 38 thereby opening the circuits to the switching relays.

Since the closure of the pullbar contacts II to I5 is eifectiveto operate the switching relays only when the slip connector fingers are in engagement, the pullbar contacts II to l5 can be employed in a telegraph system to effect the automatic and selective connection and disconnection of telegraph lines leading to various subscribers stations in the manner illustrated in Fig. 6. Fig. 6 shows a telegraph system comprising a main transmitting station A provided with a signal sending device including a transmitterdistributor 9 having a segmented distributor face-plate 55 with the usual rotating brush 56. Normally, brush 56 is prevented from rotating by latch 15 which is controlled by a release magnet 50 connectable through the usual tape con trol switch 94 and the normally open, manually operable, locking switch 14 to a battery 54. Before beginning the selection of lines for communlcation, the operator at station A will manually close switch 14. The stop segment of the faceplate 55 is connected directly to conductor l9 but the permutation code selecting segments of face-plate 55 are individually connected to the tape controlled contacts l1 which are designed to coact with a contact bar 8 connected to conductor I9.

The solid ring of face-plate 55 is connected by conductor 16 to a teletypewriter T having a printer magnet 4|, transmitting contacts 42, a break key 43, and a grounded battery 52. Teletypewriter T represents schematically the teletypewriter shown in Fig. I and is equipped with a set of stationary slip connector fingers 3| to 38, inclusive, adapted to engage with a movable set of slip fingers 2| to 28, inclusive, in the manner described above. As is shown in Figs. 1 and 6, the movable fingers 2| to 26 are connected to the pullbar contacts II to l5.

Current from battery 44 is normally applied to a contact point of each of the pullbar contacts II to |5 over a path that includes the normally unoperated armature of relay 45, conductor 86, and the pair of slip fingers 2| and 3|. Although current from battery 46 is normally applied to relay 45 over a path including the stop contact 41, which is normally closed but which opens in response to a preassigned code signal called a stop signal, such as upper case H, relay 45 remains unenergized as long as this energizing path is open at the armatures and contacts of relays 48 and 58. Relays 48 and 58 remain unenergized until the closure of either pullbar contact or l5 closes a path for current from battery 44 to pass along either conductor 51 or 84 to ground 59 or 19.

Stop contact 41 is operated by a lever, indicated at 89 in Fig. 1, which is not mounted upon the movable carriage. As is described in Morton et al. Patent 1,904,164, this stop contact 41 is operated by means which are independent of the operation of the pullbars and which are also independent of the location of the carriage along its path of travel. In this Morton et al. Patent 1,904,164, it is stated that the stop contact is operated in response to two successive figuress'hift" signals, the first conditioning a function lever for operation and the second effecting the operation of the function lever which, in turn, effects the operation of the stop contact. Varione other signals have been preassigned for operating thestop contact. such as figures-shift" and M. In the preferred embodiment of the invention, "figures-shift followed immediately by the operation of the H key on the keyboard is preassigned to efiect the operation of contact 41. Other-combinations of signals may be used to eflect the operation of the stop contact 41 but, for the purpose of this description, it will be figures-shift plus "H." Contact 41 remains open until closed in the manner described in Morton et al. Patent 1,904,164.

When relay 48 is energized, it operates its armatures and locks-up over its bottom armature through relay 45 and stop contact 41 to grounded battery 46. At the sametime, the operation of the top armature of relay 48 switches the line Ll, extending from the subscribers teletypewriter station 64, from ground 65 to conductors 66 and 68 leading to conductor l9 and transmitter-distributor 9 for the transmission and reception of permutation code signals.

Likewise, when relay 58 becomes energized, it operates its armaturesand locks up over its bottom armature to battery 46. The operation of the top armature of relay 58 switches the subscribers teletypewriter station 10 into communicative relation with the transmitter-distributor 9 by disconnecting line L2 from ground 12 and connecting it to conductors 13, 68 and I9 leading to transmitter-distributor 9. Either of these connections remains in effect until the preassigned code combination is transmitted to cause contact 41 to open thereby opening the locking-up circuits of relays 48 and 58 which will consequently release their armatures to switch lines L1 and La back to grounds 65 and 12, respectively.

In operating the system, the operator at sta-.

tion A closes the normally open, manually operable, locking switch to start his motor 96 and presses the carriage return key on the keyboard of the teletypewriter T at station A to efiect the closure of the slip fingers 2| to 28 and 3| to 38. The operator then closes the normally open, manually operable, locking switch 14 to close a path for current to pass from grounded battery 54, over switch 14, the usual tape control switch 94, through thev winding of release magnet 50, and then over slip fingers 31, 21, 28, and 38, to ground 8|. Magnet 50 thus becomes energized and operates its armature 15 thereby releasing the brush 56 for rotation over faceplate 55.

Messages that have either been previously perforated in transmitting tape by one or several tape perforators, such as perforator 85, or are now perforated in the tape, are transmitted by feeding the perforated tape through the transmitter-distributor 9. The perforations in the tape selectively operate the tape controlled contacts l1 to control the transmitter-distributor 9 and cause it to transmit the permutation code signals, perforated in the tape, over conductor |9 to conductors 68, 66, and 13. These signals are also transmitted over conductor 16 to operate the teletypewriter T which actuates its code bars 68 and pullbars 63 in accordance with the code signals.

' routing signal causes the teletypewriter 40 to select and operate the corresponding pullbar 63 which, in operating, closes its associated contact.

For example, if it is desired that a message be sent to the subscriber at station 64, then the.

routing signal, which may be the permutation code combination for some letter, such as M,

will cause'the operation of the proper pullbar 63 to close contact II. This closes a path for current from battery 44 to pass over the bottom armature of relay 45, along conductor 86, over slip fingers 3| and 2|, pullbar contact H, slip .fingers 22 and 32, along conductor 51, and then through the winding of relay 48 to ground 59.

This energizes relay 48 which operates its armatures to lock-up over its bottom armature through the winding of relay 45 and stop contact 41 to grounded battery 46. The top armature of relay 48 switches line L1 from ground 65 to conductors 66, 68 and I9 leading to transmitter-distributor 9. Station 64 is thus connected into communicative relation with transmitter-distributor 9 and a message now trans- 2,269,379 by a preassigned code signal, known as a carriage the operator that something is amiss.

' When it is desired to discontinue, or wipe out, this connection, a preassigned permutation code signal is transmitted to effect the momentary opening of stop contact 41.- This contact 41 is operated by lever 99, as was described above, only in response to a preassigned upper case signal, such as upper case H." The opening of contact 41 serves to open thelocking-up circuit of relay 48 which consequently releases its armatures. The release of the top armature of relay 48 switches line L1 from conductor 68 to ground 65. The released the bottom armature of relay 48 opens the'energizing path for relay 45 which releases its armatures; the outer top armature dis-- connects ground 71 from magnet 50, the inner top armature applies ground 11 to'conductor 18 leading to conductor l9 and thereby grounding transmitter-distributor 8, and the bottom armature applies current from battery 44 to the pullbar contacts H to l5 to activate them.

To communicate with the subscriber at station 10, transmitter-distributor 8 is caused to transmit a carriage. return signal followed by the particular permutation code signal that has been previously assigned to station 10 as its routing signal, such as the code signal for D. This routing signal is transmitted from contacts II in mitted from transmitter-distributor 9- will be recorded by the teletypewriter T1 at station 64 for a particular period of time or until this switching connection is wiped out.

The operation of the bottom armature of relay 1 48 also permits battery 46 to energize relay which, accordingly, operates its armatures. The operation of the bottom armature of relay 45 removes battery 44 from the pullbar contacts II to I5 to deactivate them so that no further transmitter-distributor 9 and is the code signal which will effect the operation of the pullbar contact l5. Closure of contact l5 closes a path from battery over conductor 86, slip fingers 3| and 2|, through contact l5, slip fingers 26 and 36, along conductor 84, and then through the winding of relay 58 to ground 19. Relay 58 operates its armatures and 100 up through its bottom armature, the top armatureswitching line L2 from ground 12 to conductors 13, 68, and I9 leading to transmitter-distributor 9. Relay 45 also operates at this time and functions in switching operations will be made at this time.

The inner topv armature of relay 45 removes round 11 from conductor 18. Ground 11 is replaced by ground 80 to complete the circuit from battery 52 through transmitter-distributor 9 and line L1. The outer top armature of relay 45 connects ground 1! to magnet 58 to maintain it energized by battery 54. This'is necessary be-v cause ground 8l is disconnected from battery 54 when the movement of the typebasket carriage 3 disengages the slip fingers.

This also serves as a safety telltale-because, if an intended line selection has not been made either through error or'failure of the selecting equipment, neither relay 48 nor 58 will be operated and, under these conditions, relay 45 cannot operate. Then, when the slip fingers are disengaged by the movement of carriage 3, neither ground 8| nor ground 11 will be connected to battery 54'. Consequently, magnet 50 would then release its armature 15 to stop the brush 56 of the transmitter-distributor 9 from rotating thereby prohibiting it from transmitting signals at this time and indicating to theoperator that the line selection has not been accomplished.

Another safety telltale is provided by the fact that the batteries 82 and 83 in lines L1 and L2 are of a polarity opposite to that of battery 52. Thus, if a subscriber's station is selected when its teletypewriter T1 or T2 is not turned on, 'or if for any other reason line current is not fed bacl; from the selected station, the transmitting mathe manner described above. This establishes a communication circuit between the transmitter-distributor 9 and the teletypewriter T2 at station 10 so that messages can be sent over this circuit as desired.

This communicative connection can be discontinued by transmitting the preassigned permutation code signal to open the stop contact 4'! which opens the locking-up circuit for relay 58. Accordingly, relay 58 releases its armatures, the top armature switching line L2 from, conductor 13 to ground 12 and the bottom armature opening the energizing circuit for relay 45. This causes relay 45 to release its armatures to perform the functions mentioned above.

If it is desired to expand the system to include other subscribers teletypewriter stations, they can be added to the system by providing them with lines similar to lines L1 and L: and relays similar to relays 48 and 58. The relays added should be connected to the slip fingers 33, 34, and 35in a manner similar to that in which relays 48 and 58 are connected to-slip fingers 32 and 36.

Although the selecting, or switching, and 58 are under the control of the main transmitting station A at which the transmitter-distributor 9 is located, once a communication connection has been established, two-way communication may be carried on.-

The system shown in Fig. 6 is designed to connect in communicative relation only one outlying station at a time to the This'is due to the fact chine T will run' open thereby serving to notify relays 48 that, as soon as a selecting relay 49 or 58 has been energized, relay 45 is energized to disconswitching function.

Fig. '1 illustrates a communication system in which a main transmitting station I is shown to have transmission channels I I I, H2, and H9 extending to a plurality of outlying teletypewriter stations IOI, I02, and I03 and is provided with apparatus for automatically and selectively connecting the station I00 to any one of the outlying stations IOI, I02, and I03 for the transmission of significant current variations. Means are also provided for enabling messages to be broadcast from station I00 to either all or to a selected plurality of stations IOI, I02, and I03. Station I00 is provided with switching relays I2I, I22, and I23 and repeating relays I3I, I32, I39. As is similar to the system shown in Fig. 6, the transmitting station I00 has a teletypewriter, comparable to that shown in Fig. 1, equipped with seven pairs of slip connector fingers I40 to I46 and pullbar contacts I50 to I53. A relay I90 is provided for establishing broadcasting connections.

To transmit a message to the outlying station It", the operator follows the same procedure described above in connection with the description of the operation of the system shown in Fig. 6; that is, the operator first closes. the normally open, manually operable, locking switch I95 to start his motor I96 and presses the carriage return key. in the teletypewriter T at station I00 to effect the closure of the slip fingers I40 to I46, inclusive. The operator then closes the normally open, manually operable, locking switch "4 to close a path for current from grounded battery I20 to pass over slip fingers I46 and I45, along conductor II9, through the winding of release magnet II9, the usual tape control switch I90, and then over switch I" to ground.

The operator then transmits the permutation code signal, such as M," that has been preassigned to select the pullbar that will operate the pullbar contact I5I to close a path from'battery I04, over the bottom armature of relay I05, over the slip fingers I44, contact I5I, slip fingers HI, and then through the winding of the switching relay I2I to ground. This energizes relay I2I which operates its armatures and locks up over its inner bottom armature through the stop contact I06 to grounded battery I01. The outer bottom armature of relay I2I closes an energizing path for relay I05 from battery I04.

The operation or the top armature of relay I05 disconnects ground IIO from conductor I09 thereby opening the short-circuit path across the repeating relays I3I, I92, and I39 and rendering efiective the path from the transmitterdistributor I99 to conductor II6 leadLlg to ground I". The operation of the bottom armature of relay I05 deactivates the pullbar contacts I50 to I59 by switching battery I04 from them to conductor II9. This maintains release magnet H9 energized after the movement of the type basket carriage has opened the slip fingers I45 and I46 to disconnect battery I from conductor II8.

The operation of the top armature of relay I2I removes ground I6I from the subscriber's loop I II and closes a path for current from battery I8I to pass through the subscribers teletypewriter T1, station IOI, over line III, top armature of relay I2I, along conductor III leading over the marking contact and armature of the repeating relay I9I, to'ground I94. Messages composed of significant current variations originating in the transmitter-distributor I99 at station I00 will pass through the windings of the repeating relays I3I, I32, and I33 to ground I" and will be repeatedby the armature of relay I3I for transmission over conductor III and line III to station IOI where they will be recorded'by the teletypewriter T1 thereat.

This communication connection can be discontinued at the will of the operator at station I00by transmitting the. preassigned permutation code signal for efiecting the opening of stop contact I06. This opensthe locking-up circuit of relay I2I which, consequently, releases its armatures to switch line III back to ground I6I and restores the system to its normal condition by deenergizing relay I05 to activate the pullbar contacts I to I59 by applying to them current from battery I04.

The operator at station I00 can selectively' connect the transmitter-distributor I99 at station I00 to the teletypewriter T2 at station I02 for communicative purposes by transmitting a carriage return signal followed by the preassigned permutation code signal, such as J, to select the proper pullbar for operating pullbar contact I52. Closure of contact I52 completes an energizing path for relay I22 from battery I04. Relay I22 operates its armatures and locks up over its inner bottom armature. The operation of the top armature of relay I22 switches line II 2 from ground I62 to conductor I12 leading to the marking contact of repeating relay I92. Operation of the outer bottom armature of relay I22 closes a path for current from battery I04 to energize relay I05 thereby opening the short circuit across the repeating relays I3I, I32, and I93.

Messages originating in the transmitter-distributor I99 will now be recorded by the teletypewriter T2 at station I02. This connection can be discontinued by transmitting the code signal for effecting the opening of stop contact I06 which forces relay I22 to release its armatures to cause line 2 to be switched from the armature of relay I32 to ground I62 in the manner described above for line III.

Line 3 extending from station I03 can be switched from ground I63 to conductor I13 leading to the marking contact of repeating relay I33 for the transmission of significant current variations in the manner described above for lines III and H2. Line II3 can be switched back to ground I69 in a manner corresponding to that described for lines III and H2.

If the operator at station I00 wishes to broadcast a message to be recorded simultaneously by the teletypewriters at a selected plurality of the outlying stations IOI, I02, and I09, he closes the particular switches I9I, I92, and I93 leading to the windings of the switching relays I2I, I22,

' I23. For example, if he wishes to broadcast to stations IM and I02,-he operates the normally open, manually operable, locking switches I9I and I92 to their closed positions as shown in Fig. 7. He then transmits a carriage return signal followed by the code signal for selecting the proper pullbar for operating the pullbar contact I50 to close a path for current from battery I04 to energize relay I90. Accordingly, relay I operates its armatures to close paths for current from battery I26 to pass over switches I9I and I92, the outer and middle top armatures of relay I90, and then through the windings of each of the switching relays I2I and I22.

Relays I2I and I22 thus become energized and operate their armatures to lock-up and switchlines III and H2 to the marking contacts of repeating relays I 3I and I32, respectively, in the manner described above. Relay I05 also operates its armatures at this time to deactivate the pullbar contacts I50 to I53 and to remove the shortcircuit across the repeating relays I3I, I32, and I33. This causes relay I90 to release its armatures. Messages now originating in the transmitter-distributor at station I will be simultaneously repeated by relays I3I and I32 over lines I II and H2 and will be recorded practically simultaneously by the teletypewriters at the selected stations IOI and I02. To broadcast to all three stations, the operator would close all three switches I9I, I92, and I93.

This broadcast connection can be discontinued and the system restored to its normal condition by transmitting the preassigned signal to effect the opening of stop contact I06 which opens the locking-up circuits of each of relays I2I and I22 thereby switching lines III and H2 to grounds I6I and I62, respectively. At the same time, relay I is deenergized and releases its armatures to short-circuit the repeating relays I3I, I32, and I33.

It is to be understood that the system shown in Fig. 7 is not limited to only three outlying stations. More subscribers stations can be added. if desired, by adding relays corresponding to the switching relays I2I, I22, and I23 and by inserting corresponding additional repeating relays between relays I32 and I3I. This would require the addition to the system of additional pullbar contacts, slip fingers, conductors, et cetera.

The system shown in Fig. 7 can be modified to permit the operator at the main transmitting station to selectively connect his transmitter, by means of permutation code signals which effect the operation of electrically operated means, to any one of the outlying stations or to any desired combination of the outlying stations for simultaneous communication thereto. This modification is shown in Fig. 8 which is designed to establish a broadcasting circuit through the use of a. multi-signal permutation code and includes the main transmitting station 290 having transmission channels 2I I, 2I2, and 2I3 extending to the outlying teletypewriter stations 294, 295, and 296. Station 290 is also provided with switching relays 22I, 222, and 223 and repeating relays 23I, 232, and 233 in addition to a teletypewriter T similar to that shown in Fig. 1. As is indicated by the dot-dash lines, the equipment comprising the slip connector fingers 240 to 246 and pullbar contacts 250 to 253 is a part of the teletypewriter T. Station 290 is further provided with a relay 205 for controlling the activation of the pullbar contacts.

The sets of slip connector fingers 240 to 246 are so constructed as to remain in mutual engagement while the movable type basket travels during its first few letter space movements. The particular number of letter space movements that the slip connector fingers must remain in engagement is equal to one plus the maximum number of outlying stations to be connected into a broadcasting circuit. Thus. in the circuit shown in Fig. 8, the slip fingers must remain in engagement while the type basket is traveling its first four letter space movements. In other words, the selecting means is effective-only when the path 01' travel.

T0. transmit a mess ge to the outlying station 294, the operator at station 290 first closes the manually operable, locking switch 298 to start his motor 291 and then presses the carriage return key on his teletypewriter'keyboard to bring the sets of slip fingers 240 to 246 into mutual engagement. The operator next closes the normally open, manually operable, locking switch 214 to close a path for current from battery 220 to pass over slip fingers 246 and 245, over conductor 2I6, through the winding of the release magnet 2I9, the usual type oi tape control switch 280, and then over switch 214 to ground thereby energizing magnet 2I9 and conditioning the transmitter-distributor 299 for operation.

The operator follows this with the permutation code signal, such as M that has been assigned to effect a selection of the proper pullbar to operate contact 25I thereby closing a path for current from battery 201 to pass over the stop contact 206, contact of the nonoperated relay 205, slip finger 244, pullbar contact 25I, slip finger I, and then through the winding of relay 22I to ground. This serves to energize the switching relay 22I which operates its armatures and locks up over its bottom armature and then over stop contact 206 to grounded battery 201. The operation of the top armature of relay 22I removes ground 26I from the subscribers loop 2 and closes a path for current from battery 28I to pass through the outlying subscribers teletypewriter set T1 at station 294, over line 2| I, top armature of relay 22I, along conductor 21! leading to the marking contact and armature of repeating relay 23I and then to ground 284.

The operator at station 290 then transmits the permutation code signal, such as C, that has been assigned to eflect the selection of the proper pullbar to operate contact 250 thereby closing a path for current from battery 20! to pass over the'stop contact 206, contact of the non-operated relay 205, slip finger 244, pullbar contact 250, slip finger 240, and then through the winding of relay 205 to ground. This serves to energize the control relay 205 which operates its armatures and locks up over its upper armature and then over stop contact 206 to grounded battery 201.

The lower armature of relay 205 applies battery 204 to conductor 2I8 so as to hold magnet 2I9 energized after the type basket has moved along its path of travel a distance suflicient to disengage the slip connector fingers 240 to 246 thereby disconnecting battery 220 from magnet 2I9. This also serves as a safety telltale in the event no line selection was made either through error or failure of the selecting equipment as, under such conditions, no current would be supplied to the release magnet 2I9 which would then release its armature to stop the transmitter-distributor 299 thereby indicating to the operator at station 290 that the line selection has not been accomplished.

At the same time the operation of the upper armature of relay 205 opens the path from bat tery 201 to the slip fingers 240 to 246 thereby deactivating the pullbar contacts 250 to 253 so that their subsequent operation will be ineffective to accomplish any useful function. The system is now placed in condition for communication thereover.

This communicative connection can be wiped out by transmitting the preassigned permutation code signal for effecting the opening of the effecting the energization of relay 222.

stop contact 206. This opens the locking-up circuits of relays 205 and 22! which release their armatures, the top armature of relay 22! switching the subscriber's line 2!! from conductor 21! to ground 26!. The lower armature ofrelay 205 disconnects battery 204 from conductor 2|8 while the upper armature allows the top contact of relay 205 to connect battery 201 to the pullbar contacts 250 to 253. The pullbar contacts 250 to 253 are thus activated once moreand the system restorted to its normal condition. I

The operator at station 290 can cause messages transmitted from the transmitter-distributor 299 at station 290 to be automatically routed to the. teletypewriter station 295 by preceding the messages with the carriage return signal followed by the preassigned code signal, such as J, for effecting the energization of relay 222 and then the preassigned code signal, such as C," for effecting the operation of relay 205. After the desired number of messages have been sent to station 295, this automatic routing of messages can be discontinued by transmitting the preassigned code signal, such as H, to effect the opening of the stop contact 206.

The destination of messages transmitted from the transmitter-distributor 299 at station 290 can also be automatically assigned to the teletypewriter station 296 by following the same procedure as described above'except that this time .the operator uses the preassigned code signal,

such as D, for effecting the energization of relay 223. This routing of messages can be terminated in the manner described above.

Messages originating at station 290 can be broadcast for simultaneous reception by any desired combination of two or more of the outlying stations 294, 295, and 296. To efiect broadcast routing of messages, the operator at station 290 follows somewhat the same procedure described above by first transmitting a carriage return signal. This is followed by the preassigned code signals assigned to the particular stations that are desired to be connected into a broadcasting circuit. For example, if it is desired to broadcastto stations'294 and 296 simultaneously, the operator sends the particular signals, such as M- and D, designed to effect first the energization of relay 22! and then the energization of relay 223. These relays 22! and 223 operate their armatures to switch current from batteries 28! and 293 from grounds 26! and 263 to'conductors 21! and 213 leading to the armatures of the repeating relays 23! and 233 and then to grounds 284 and 236.

The operator then transmits the code signal to efiect the energization of relay 205 which operates its armatures to deactivate the pullbar contacts 250 to 25! by disconnecting battery201 therefrom. Messages originating in the transmitter-distributor 299 at station 290 will now be repeated simultaneously over the communication channels 2!! and H3 for reception by the 'teletypewriters at stations 294 and 296. This broadcasting connection can be discontinued in the manner described above by transmitting the 205 for deactivating the pullbar contacts 250 to 253. Current from battery 282 would thus be switched from ground 262 to conductor 212 leadover the armature of relay 232 to ground The operator at station 290 can selectively connect transmitter-distributor 299 to any of the outlying stations 294, 295 and 296 in any combination that may be desired for thebroadcasting of messages. The system is not limited to only three outlying stations as more subscribers stations may be added to the system by inserting additional repeating relays between relays 232 and 23! and by adding additional pullbar contacts, slip connector fingers, switching relays, and other equipment similar to that described above for stations 294,. 295, and 296.

\ Figs. 9 and 10 show a communication system having a main transmitting teletypewriter station 300 with a plurality of outlying teletypewriter subscribers stations 400, 500, and 600 connected thereto in series by communication lines 3!2, M2, and M2. Lines M2, M2, and 512 "are really all part of the same communication channel but, for the purpose of improving the clarity of the description, these component parts of the main communication line are separately numbered. A plurality of other communication channels a and b also extend from station 300 and each of these channels a and b has connected therein one or more subscribers teletypewriter stations, such as those indicated at TAl, TA2, Tea, T131, T132, and T33, similar 60 S68 tions 300, 400, and 500. Selecting means are provided for enabling the operator at the main station 300 to select for communicative purposes any single station on any of the channels and to exclude from communication at that time all of the other stations. During idle periods, each of 'the channels 3!2, a, and b are connected to a 7 ground 334, 338, and 339, respectively. The system also includes broadcasting means for broadcasting a message for nearly simultaneous reception by the teletypewriters at a plurality of the subscribers stations on one or more of the channels.

For example,- if the operator at the main transmitting station 300 wished to effect a communicative connection between his station and station 500 to the exclusion of stations 400 and 600, the

operator would first close his manually operable,

locking switch 395 to start his motor 396. -The particular signal that has been assigned to opoperator would then press his carriage return key on his teletypewriter keyboard to bring the slip fingers 340 to 346, inclusive, into mutual engagement. Next the operator would close the manually operable, locking switch 314 to close a path for current from battery 320 to pass over switch 314, the usual tape control switch 390, through the winding of release magnet 3l9, outer bottom contact and armature of relay 323 and relay 354 and relay 364 in parallel, slip fingers 344 and 345, and then over the bottom armatures of slowrelease relays 322 and 326 and 328 to ground 335.

. This releases the brush arm ofthe transmitterdistributor 399 for rotation for the transmission of permutation code signals but, at this time, the path from transmitter-distribut-or 399 terminates in ground 331..

The operator follows this with a channel selecting permutation code signal, such as D,"

that has been preassigned to efiect the momentary closure of the pullbar contact 350 thereby closing a path for current from battery 304 to pass over the bottom armature of relay 305, slip connector finger 343, contact 350, slip finger 340, and-then through the winding of relay 323 to ground 330, thereby energizing relay 323. Relay 323 operates its armatures and locks-up from ground 330, through its winding, over its inner bottom armature, stop contact 306, and then to grounded battery 301.

The operator then sends the preassigned code signal, such as K, to efiect the closure of pullbar contact 353 resulting in the energization of relay 305 which operates its armatures and locksup from battery 301 over its inner top armature to ground 358. The operation of the bottom armature of relay 305 disconnects battery 304 from the pullbar contacts 350 to 353 to deactivate them, thereby rendering them inefiective to perform any switching functions during the subsequent transmission of permutation code signals. The operation of the outer top armature of relay 305 removes ground 331 from the path leading from transmitter-distributor 399. Relay 305 remains energized along with relay 323 until a stop signal, such as upper case H, is sent to effect the opening of stop contact 306.

The operation of the inner top armature of relay 323 removes ground 334 from the line conductor 3l2 and connects line 3I2 over the inner top armature of relay 323, over the face-plate of the transmitter-distributor 399, and then through the winding of the teletypewriter line magnet 381 to grounded battery 38!. The outer bottom armature of relay 323 substitutes ground 332 in place of ground 335 at the end of the path from grounded battery 320 through the release magnet 3!9. This serves as a safety telltale to guard against a election failure as explained above and also serves to maintain release magnet 3l9 energized after the movement of the type-basket carriage has opened the slip fingers 344 and 345 to disconnect ground 335 from slip finger 344. The operation of the outer top armature of relay 323 applies ground 33! to complete a circuit for current from battery 308 to energize slow-release relay 325.

Relay 325 operates its armature to close a path from grounded battery 355, through the winding of slow-release relay 322, and then over the armature of relay 325 to ground 336. This energizes relay 322 which operates its armatures, the bottom armature removing ground 335 from the slip finger 345 'while the top armature removes ground 334 from the conductor 382 leading to a contact of relay 323. This completes the selection of the line 3!2 for communicative purposes while channels a and b remain connected to grounds 338 and 333, respectively.

The preassigned code signal. such as D, having effected the selection of the communication channel 3! 2 at station 300, the operator at station 300 now has a choice of either broadcasting a message for reception by all of the stations 400, 500, and 600 that are connected in series on the line or else selecting one of the stations 400, 500, or 600 to receive a message to the exclusion of the other stations. If the operator wishes to send a message for reception by only one out lying teletypewriter station, such as station 500, a carriage return signal is first transmitted to bring the slip fingers mounted in the teletype-r writers T1, T2 and T3 at stations 400, 500, and 600, into mutual engagement. If the carriages of the teletypewriters at these stations were already in the return position, it would not be necessary to send a carriage return signal at this time. However, as a safety precaution, it is advisable to send such a signal in all cases.

This is followed by the station selecting permutation code signal, such as Rf, that has been preassigned to effect the operation of the R" pullbar in each of the connected outlying teletypewriters T1, T2 and Ta thereby closing the R" pullbar contacts 45!, 552, and 65!. At station 500, the closure of contact 552 completes an and locks-up from battery 501, stop contact 506,

winding of relay 505, top armature and contact of relay 523, and then over the outer bottom armature of relay 505 to ground 53!. The operation of the inner bottom armature of relay 505 disconnects battery 504 from the pullbar contacts 550 and 55! and the operation of the top armature of relay 505 disconnects ground 530 from pullbar contacts 552 and 553. This deactivates the pullbar contacts 550 to 553 so that the operation of these contacts during the subsequent printing of a message will not be effective to perform any switching functions. The apparatus at station 500 is thus placed in condition for the printing of a message transmitted from station 300.

As was tated above, all of the R pullbar contacts in the connected teletypewriters T1, T2 and T3 are operated in response to the transmission of the fR code signal. At station 400, the closure of the R pullbar contact 45! closes a path for current from battery 404 to pass over the inner bottom armature of relay 405, slip finger 44!, contact 45!, slip finger 440, through the winding of relay 423, and then over the outer bottom armature of relay 405 to ground 43!. This serves to energize relay 423 which operates its armatures and locks-up over a path traced from grounded battery 401, stop contact 406, winding of relay 405, top armature and winding of relay 423, and then over the outer bottom armature of relay 405 to ground 43! thereby energizing relay 405 which operates its armatures.

The operation of the inner and middle bottom armatures of relay 423 disconnects the polarized line relay 424 from line conductors 3l2 and H2. Accordingly, line relay 424 moves its armature toits spacing contact under the influence of the biasing current which passes from battery 351 through the biasing winding of relay 424 to ground 432. At the same time, the operation of the outer bottom armature of relay 423 switches slow-release relay 422 into the line circuit by closing a path for line current to pass from line conductor 3l2, over the outer bottom armature and contact of relay 423, winding of relay 422, and then to line conductor 2 thereby energizing relay 422. Relay. 422 operates its armatures, the bottom armature applying ground 435 to conductor 484.

Also at this time, as was stated above, relay 405 becomes energized and operates its armatures. The operation of the inner bottom armature of relay 405 removes battery 404 from pullbar contacts'450 and 45! and the operation of the top armature removes ground 430 from pullbar contacts 452 and 453 thereby deactivating the pullbar contacts 450 to 453. The operation of the outer bottom armature of relay 405 removes ground 43! from the locking-up circuit through relay 423 and effects the substitution of ground 435 over conductor 484. This holds both relays 465 and 423 operated under the control the stop contacts 466 and relay 422. Since relay 422 is or the slow-to-release type, its armatures will not be released during the momentary interruptions 01 the line current when signals are sent over the line.

The operation of the top armature of slowrelease relay 422 closes a path for current to pass from grounded battery 486, over the top armature of relay 422, through the winding of relay 485, and then over the spacing contact and armature of line relay 424 to ground 433 thereby energizing relay 485. Relay 485 operates its armatures and locks-up from grounded battery 486, bottom armature and winding of relay 485, and then over the armature of line relay 424 to ground 433. The operation of the top armature of relay 485 closes a path for current to pass from battery 48l, through the winding of theteletypewriter magnet 481, and then over the top armature of relay 485 to ground 434. This serves to keep the teletypewriter at station 466 running closed during the time that it remains switched out of the communication channel.

The operation of the R pullbar contact 65l at station 666 will perform the same functions at station 666 that the operation of contact 45l performed at station 466. The line relay 624 will be switched out of the communication circuit and the line circuit will be switched to pass through the winding of relay 622 and then over conductor 612 to grounded battery 68!.

This completes the preparation of the circuit for the transmission of significant current variations from grounded battery 38! at station 366, through the teletypewriter line magnet 381 and the transmitter-distributor 399, inner top armature of relay 323, line conductor 3l2, outer bottom armature of relay 423 at station 466, winding of relay 422, out over line conductor 2 to station 566, inner bottom armature of relay 523, line winding of the polarized line relay 524, middle bottom armature of relay 523, out over line M2 to station 666, outer bottom armature of relay 623, winding of slow-release relay 622, and then over conductor M2 to. grounded battery 68L Messages comprising significant current variations can now be transmitted from the transmitter-distributor 399 at station 366 over the line circuit just traced and will be received and printed by the teletypewriter T2 at station 566 but will not be printed by the teletypewriters T1 and T3 at stations 466 and 666.

At the conclusion of the transmission of messages between stations 366 and 566, a disconnect, or stop, signal, such as upper case H" is transmitted to wipe out the selection by efiecting the opening of the stop contacts 366 and 566. At station 366, the opening of stop contact 366 opens the locking-up circuit of relays 365 and 323 and causes them to release their armatures. The release oi the bottom armature of relay 365 applies current from battery 364 to the slip finger 343 so that, when a carriage return signal is transmitted, the pullbar contacts 356 to 353 will again be activated. The release of the outer bottom armature of relay 323 removes ground 332 from the circuit through the release magnet 3l9.

Since the path from ground 335 is open at the bottom armature of slow-release relay 322, release magnet 3l3 will release its armature which will catch the brush of the transmitter-distributor 383 to prevent it from further rotation at this time. The release of the inner top armature of relay 323 opens the path from the transmitterdistributor 383 to line conductor 3|2. At the same time, the release 01' the outer top armature of relay 365 connects ground 33! to the path leading through the transmitter-distributor 388. This serves to .keep the teletypewriter-T at station 366 running closed. The release of the inner top armature of relay 323 also switches the line conductor M2 to conductor 332 leading to the top contact of slow-release relay 322, but, since the armatures of relay 322 are now operated, the line circuit is left open until such time as relay 322 releases its armatures to supply ground 334 to line conductor 3|2.

At the same time, the release of the outer top armature of relay 323 removes ground 33I from the energizing circuit through slow-release relay 325 which releases its armature after a time delay in accordance with its slow-release characteristics. This removes ground 336 from the energizing circuit through slow-release relay 322 which, after its inherent time delay, releases its armatures. The bottom armature of relay 322 applies ground 335 to slip finger 345 thereby preparing a circuit for applying ground 335 to the release magnet 3l9 when the slip fingers 344 and 345 are closed by the return of the carriage. The release of the top armature of relay 322 applies ground 334 to conductor 382 and line conductor 312 thereby closing a path for current from grounded battery 68l to flow over the line to ground 334. Due to the two periods of delay in effecting the release of the armatures of relays 325 and 322, the line was left open for an appreciable period.

This relatively long open period is necessary in order to eifectuate the release of the armatures of slow-release relays 422 and '622. At station 466, slow-release relay 422 releases its armatures in response to the long opening of the line. The release of the bottom armature disconnects ground 435 from the energizing circuit through relays 465 and 423 which release their armatures. The release of the top and inner bottom armatures of relay 465 applies battery 464 to slip finger 4 and ground 436 to slip finger 443 so that the pullbar contacts will be activated again when the type-basket carriage moves to its return position. Ground 43l is applied to relay 423 by the release of the outer bottom armature of relay 466 but this accomplishes no useful function at this time.

As was just stated, relay 423 also releases its armatures, its outer bottom armature switching relay 422 out or the line circuit so that it is not energized by the subsequent closure or the line. The release of the inner and middle bottom armatures of relay 423 switches the line winding of the polarized line relay 424 into the line circuit.

Relay 485 remains locked-up until the communication line is closed. When the line is closed, the line current will cause the polarized line relay 424 to move its armature to its marking contact. This switches the circuit through the teletypewriter magnet 481 to ground 433 and also opens the locking-up circuit of relay 485 which will then release its armatures to complete the restoration of the equipment at station 466 to its normal condition. I

The long opening of the line accomplishes the same results at station 666 as was just described for station 466. It can thus be understood that this long opening or the line must be or such duration that all the relays, except relays 485 and 685, at stations 400 and 600 will have time to release their armatures. The circuit is designed to allow the holding relays 485 and 685 to remain energized during the interval that the line is open as this holdsthe teletypewriter circuits at stations 400 and 500 closed and prevents the teletypewriters T1 and Ta from running open for a short time which might cause them to print a false character when the line current is restored.

During this time, the stop signal such as upper case H, is received at station 500 and effects the operation of the stop contact 506 to open its upper contact while closing its lower contact. The opening of the top part of stop contact 506 opens the energizing circuit of relay. 505 which, accordingly, releases its'armatures. The release of the top and inner bottom armatures of relay 505 applies battery 504 to slip finger and ground 530 to slip finger 543 so that the pullbar contacts 550 and 553 will be activated again when the type-basket carriage moves to its return position. Ground 53l is applied to relay 523 by the release of the outer bottom armature of relay 505 but this performs no usefulfunction at this time.

The closure of the lower part of stop contact 506 completes a circuit for current from battery 50'! to pass over this lower portion of stop contact 506, through the winding of relay 585, and then over the spacing contact and armature of relay 524 (relay 524 moves its armature to its spacing contact when relay 323 at station 300 releases its armatures) to ground 533. Relay 585locks-up over a path traced from grounded battery 586, bottom armature of relay 585, winding of relay 585, and then over the spacing contact and armature of relay 524 to ground 533.

The operation of the top armature of relay 585 closes a path for current to pass from grounded battery 58!, through. the winding of the line magnet 581, and then over the'top armature'of relay 505 to ground 534. This serves to keep the teletypewriter T2 at station 500 running closed while the line is open at this time. This local teletypewriter circuit is held closed until relay 322 at station 300 releases its armatures to apply ground 334 to the line conductor 3l2 to cause the polarized line relay 524 to move its armature to its marking contact to apply ground 533 to the local teletypewriter circuit while, at the same time, opening the locking-up circuit of relay 585. Consequently, relay 585 will now release its armatures but the local teletypewriter circuit will be held closed by the application of ground 533.

If the operator at station 300 wishes to communicate with a subscriber at the outlying sta- 500 by transmitting the preassigned stop signal,

- such as upper case H.

In a similar manner, the apparatus at station 600' may be conditioned for exclusive connection with that at station 300 by transmitting another station selecting signal, such as Q, that has been preassigned to effect the operation of the Q pullbar contact 652 at station 600 and contacts 450 and 550 at stations 400 and 500. The operation of these contacts 652, 450 and 550 performs functions similar to those described aboveto place station 600 in condition for communication to the exclusion'of stations 400 and 500. This connection can likewise'be discontinued by tion 400 to the exclusion of stations 500 and 600,

the same procedure is followed except that, instead of sending the R code signal, the operator transmits a different station selecting signal, such as S, that has been preassigned to eflect the operation of the S pullbar contact 452 at station 400 and contacts and 650 at stations tion of contacts 55! and 650 will cause the line windings of the polarized line relays524- and 524 to be switched out of the line circuit and will also cause the line circuitto pass through-the wind ings of relays 522 and 622 in the. manner de This communication connection can be discondition for the printing of a message.

transmission of the preassigned stop signal. Whenever a message is of interest to the subscribers at all of the outlying stations 400, 500 and 500, the operator at station 300 can connect them all into a broadcasting connection to enable each of them to receive the message practically simultaneously. This broadcasting connection is efiected by transmitting a code signal, such as B, that has been preassigned to eflect the operation of each of the B pullbar contacts 453, 553 and 653.

At station 400, operation of contact 453 closes a path for current from grounded battery 401 to pass over stop contacts 406, through the winding of relay 405, slip finger 442, contact 453, slip finger 443, and then over the top armature of relay 405 to ground 430. This energizes relay 405 which operates its'armatures and locks-up over the top armature of relay 423 and outer bottom armature of relay 405 to ground 43!. The operation of the top armature of relay 405 removes ground 430 from slip finger 443 and the opera tion of the inner bottom armature disconnects battery 404 from slip finger 4 thereby deactivating the pullbar contacts 450 to 453, inclusive. This places the apparatus at station 400 in con- Similarly, the operation of the pullbar contact 553 closes an energizing path for relay 505 which operates and locks-up. This places the equipment at station 500 in readiness for communication. Likewise, operation of pullbar contact 653 effects the energization of relay605 and conditions the apparatus at station 600 for communication purposes.

Each of the three stations 400, 500, and 600 is thus conditioned for communication over the communication channel extending to station 300. Consequently, any message now transmitted by the transmitter-distributor 399 at station 300 over line conductors 3l2, 4|2, 5l2 and 612 will be recorded practically simultaneously at each .of the stations 300, 400, and 500 by the teletypewriters T1, T2, and T3 thereat.

This broadcast connection can be discontinued by transmitting the stop signal, upper case H, which will perform at stations 300 and 500 the functions previously described above and will accomplish the same functions at stations 400 and 600 as were described above in connection with station 500. The system is thus restored to its normal condition.

Other communication channels, such as a and b which are similar to the channel comprising line conductors 3|2, M2, 512 and (H2, each hav- .ing connected therein a plurality of other outlying teletypewriter subscribers stations, repre- -T,'sented at TAl, TA2, TA3, T131, T152 and T33 and 5 which ar similar to stations 400, 500 and 600, scribed above in connection with station 400.

may be selected by the operator at station 300.

'Channel a passes to ground 338 over the inner top contact of relay 354 which is similar to relay 323 and has ts winding connected to slip finger Channels and b can be separately selected by causing either the pullbar contact 351 or the puilbar contact 352 to be operated by sending the proper preassigned channel selecting permutation code signal which may be J or M," respectively, followed 'by the signal K for effecting the energization of relay 305. Closure of contact 35! effects the energization of relay 354 which operates its armatures to switch channel a from ground 338 to the transmitter-distributor 399 in the manner similar to that described above in connection with the operation of the armatures of relay 323. Communication can now take place over channel a ina manner similar to that described previously after which the communication connection may be terminated by transmitting the stop signal, upper case H. Likewise, closure of contact 352 causes relay-364 to operate its 'armatures to switch channel b from ground 339 to the transmitter-distributor 399. After transmitting messages for reception by either one teletypewriter or all of the teletypewriters on the channel b, this communication connection can be discontinued by transmitting the stop signal.

If it is desired to broadcast over more than one channel at a time, the operator can connect a selected plurality of the channels to the transmitter-distributor 399 at one time. To accomplish this, the operator presses, for example, the D, M and K keys on the teletypewriter keyboard in the teletypewriter T at station 303. The operation of the D and M keys effects the closure of contacts 350 and 352 which, in turn,effects the energization of switching relays 323 and 364 to connect channels M2 and b to transmitter-distributor 399. Operation of the K contact 353 causes relay 305 to operate and lock-up to remove ground 331 from the transmitter-distributor 399 and to deactivate the pullbar contacts 359 to 353. Selections of oneor more stations on each of channels M2 and b may be made in the manner described above. These connections can be discontinued by transmitting the stop signal.

Other channels and stations can be added to the system in a similar manner if desired. Various other modifications may be made without exceeding the scope of the invention. Consequently, the invention is to be limited only by the claims appended hereto.

What is claimed is:

1. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, a plurality of control means mounted on said movable carriage for determining which of the teletypewriters at theseother stations shall record the signals transmitted from the first station during a particular period' of time.

2. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, av pluralityof control means mounted .on said movable carriage for eiiecting a selection as to which of the teletypewriters at these other stations shall record the signals transmitted from the first station during a, particular interval of time, means for wiping out said selection said wiping out means comprising only one mechanically operated contact, and means for mounting said contact in the teletypewriter at the firststation in a location other than on the movable carriage.

3. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage-along a. fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, control means mounted on said movable carriage for determining which of the teletypewriters at these other stations shall record the signals transmitted from the first station during a particular period of time, operating means for effecting the operation of said control means, and means for permitting the operation of said control means to be effective to accomplish its switching function only when the carriage is at a preassigned point on its path'of travel.

time, operating means for effecting the operation of said control means, and means for permitting the operation of said control means to be effective to accomplish its switching function only when the carriage is at certain preassigned points on its path of travel.

5. A communication system including in commination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, control means mounted on said movable carriage for effecting a selection as to which of the teletypewriters at these other stations shall record the signals transmitted from the first station during a particular period of time, operating means for effecting the operation of said control means, means for permitting the operation of said control means to be effective to accomplish its switching function only when the carriage is at a preassigned point on its path of travel, means for wiping out said selection, and operatingmeans for effecting the operation of said last-mentioned means independently of the location of the carriage along its path of travel.

6. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a' teletypewriter, means for transmitting signals from the first station to these other stations, a control contact mounted on said movable carriage for determining whether a tele-.

typewriter at one of the other stations shall record signals transmitted from the first station during a particular period of time, and means for operating said control contact.

'7. A communication system including in com-- bination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving'said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to cord the signals transmitted irom the first station during a particular period of time, and means for selectively operating the control contacts in response to the selective operation of certain preassigned pullbars.

11. A communication system including in combination a first teletypewriter station having a teletypewriter equipped with a plurality oi pullbars and a movable carriage for carrying the pullbars, means for selectively operating the pullbars, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a telethese other stations, a control contact mounted on said movable carriage for determining whether a teletypewriter atone of the other stations typewriter, mears for transmitting signals from the first station to these other stations, a plurality 01' control contacts mounted on the movable carriage for eflecting a selection as to which of the teletypewriters at these other stations teletypewriter equipped with a plurality oi! pullbars and a, movable carriage for carrying the pullbars, means for operating the pullbars, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, a control contact mounted on the movable carriage for determining whether a teletypewriter at one of the other stations shall record thesignals transmitted from the first station, and means for operating the control contact in response to the operation of a preassigned pullbar. g

9. A communication system including in combination a first teletypewriter station having a teletypewriter equipped with a plurality of pullbars and a movable carriage for carrying the pullbars, means for operating the pullbars, means for moving said carriage along a fixed path of travel, a lever mounted in said teletypewriter in a location other than on the movable carriage, means for operating said lever independently of the operation of the pullbars, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, 9. control contact mounted on the movable carriage for determining whether a teletypewriter at one of the other stations shall record signals transmitted from the first station during a particular period of time, means for operating the control contact in response to the operation of a preassigned pullbar, means for terminating the effect of the operation of said control contact, and means for operating said last-mentioned means in response to the operation of said lever.

10. A communication system including in combination a first teletypewriter station having a teletypewriter equipped with a plurality of pullbars and a movable carriage for carrying the pullbars, means 'for selectively operating the pullbars, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, a plurality of control contacts mounted on the movable carriage for selectively determining which of the teletypewriters at these other stations shall reshall record the signals transmitted from the first station during a particular period or time, means for selectively operating the control contacts in response to the selective operation of certain of the pullbars, means for wiping out said selection, and operating means for operating said last-mentioned means independently of the operation of the pullbars.

12. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a control contactmounted on said movable carriage, governing means at the first station mounted other than on said movable carriage, a plurality of other teletpyewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, means for completing an electrical connection between said control contact and said governing means under certain conditions, and means for operating said control contact to effect the operation of said governing means when said electrical connection has been completed for determining-whether a teletypewriter at one of the other stations shall record signals'transmitted from the first station during a particular period of time.

13. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a control contact mounted on said movable carriage, governing means at the first station mounted other than on said movable carriage, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, a slip connector finger mounted on a fixedly located portion of the teletypewriter at the first station, another slip connector finger mounted on said movable carriage, means for bringing said slip connector fingers into mutual engagement for completing an electrical connection between said control contact and said governing means under certain conditions, and means for operating said control contact to effect the operation of said governing means when said electrical connection has been completed for determining whether a teletypewriter at one of the other stations shall record signals transmitted from the first station during a particular period of time.

14. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a control contact mounted on said movable carriage, governing means at the first station mounted other than on said movable.car-' riage, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, a slip connector finger mounted on a fixedly located portion of the teletypewriter at the first station, another slip connector finger mounted on said movable carriage, means for bringing said slip connector fingers into mutual engagement for completing an electrical connection between said control contact and said governing means only when thecarriage is at a preassigned point on its path of travel, and means for operating said control contact to effect the operation oi. said governing means when said electrical connection has been completed for determining whether a teletypewriter at one of the other stations shall 'record signals transmitted from the first station during a particular period of time.

15. A communication system including in combination a first teletypewriter station having a teletypewriter equipped with a movable carriage, means for moving said carriage along a fixed path of travel, a plurality of control contacts mounted on the movable carriage, governing means at the first station mounted other than on said movable carriage, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, a plurality of slip connector fingers mounted on a fixedly located portion of the teletypewriter at the first station, a plurality of slip connector fingers mounted on said movable carriage, means for bringing said slip connector fingers into mutrial-engagement for completing electrical connections between said control contacts and said governing means only when the carriage is at certain preassigned points on its path of travel, and means for selectively operating any of said control contacts to effect the operation of said governing means when said electrical connections have been completed for selectively determining which of the teletypwriters at the other stations shall record signals transmitted from the first station during a particular period of time.

16. A communication system including in combination a first teletypewriter station, having a teletypewriter with a movable carriage, means (or moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other sations, said teletypewriter at the first station having a plurality of pullbars, each of said pullbars having an unoperated position and an operated position, a set of spring contact points, an extension arm secured to one of the contact poins and normally placed in engagement with a certain one of said pullbars in its unope'rated position, and means for moving said certain pullbar to its operated position to allow v the extension arm to move the contact point to which it is secured for effecting a selection as to which of the telet pewriters at these other stations to record signals transmitted from the first station during a particular period of time.

each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, said teletypewriter at the first station having a plurality of pullbars, each of said pullbars having a first position and a second position,'a set of spring contact points having the force oi the spring tending to close the contact points, an extension arm placed in engagement with a certain one or said pullbars in its first position and secured to one of the contact points, means for moving said certain pullbar to its second position to allow the extension arm to move to close the contact points for determining whether a teletypewriter at one 01' the other stations shall record signals transmitted from the first stationduring a particular period of time, and restoring means for effecting the return of said certain pullbar to its position for moving the extension arm to force the contact points open.

18. A communication system including in combination a first teletypewriter station having signal transmitting means and a teletypewriter with a manually operated keyboard, a second teletypewriter station having a communication channel extending to the first station, said second station also having transmitting means for transmitting signals over said communication channel, means for closing a path to shunt signaling current in the signal transmitting means at the first station away from said communication channel, control means at the first station for opening said shunting .path, and operating means controlled by the teletypewriter at said first station in response to signals generated by the transmitting means thereat for operating said control means.

' 19. A communication system including in combination a first teletypewriter station, a plurality of other teletypewriter stations, said first station having transmitting. means for transmitting signals from said first station to these other stations, operating means for operating the transmitting means, selective switching means at the first station for eflecting a selection as to which of the teletypewriters at these other stations shall record the signals transmitted by the first station during a particular period of time, and safety means for prohibiting the transmission of signals by said transmitting means in the event of a failtire of an intended switching operation.

20. A communication system including in combination a first teletypewriter station, a communication channel extending from the first station, a plurality of other teletypewriter stations connected into said channel, each of these other stations having a teletypewriter with a movable carriage, means for moving each carriage along 'a fixed path of travel, each carriage having a 17. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations return position, means for transmitting signals from the first station over said communication channel to these other stations, each of the other stations having control means located thereat for determining whether the teletypewriter at that station shall record signals transmitted from the first station during a particular period of time, and operating means for operating each of the control means independently of all the other control means in response to a carriage return signal transmitted from the first station and followed by a signal that is individual to each control means.

21. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel,

said carriage having a return position, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, control means mounted on said movable carriage for determining which of the teletypewriters at these other stations shall record the signals transmitted from the first station during a particular period of time, operating means for effecting the operation of said control means, and conditioning means for rendering the operation of said control means effective to accomplish its control function only when the carriage is in its return position.

22. A communication system including in combination, a first teletypewriter station having a teletypewriter equipped with a plurality of pullbars, means for selectively operating the pullbars individually, means for moving said carriage along a fixed path of travel, said carriage having a return position, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, a control contact mounted on said movable carriage for determining whether a teletypewriter located at one of the other stations shall record the signals transmitted from the first station during a particular period of time, operating means for operating the control contact in response to the operation of a preassigned pullbar, and conditioning means for rendering the operation of said control contact effective to accomplish its control function only when the carriage is in its return position.

23. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to the other stations, switching means at the first station mounted other than on said movable carriage for determining which of theteletypewriters at these other stations shall record the signals transmitted from the first station during a particular period of time, control means mounted on said movable carriage, connecting means for establishing an electrical connection between said control means and said switching means for enabling said control means to control the operation of said switching means,'and operating means for operating said control means to effect the operation of said switching means after said electrical connection has been established.

24. A communication system including in combination a first teletypewriter station having a teletypewriter with a movable carriage, means for moving said carriage along a fixed path of travel, said carriage having a return position, a plurality of other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to these other stations, switching means at the first station mounted other than on said movable carriage for determining which of the teletypewriters at these other stations shall record the signals transmitted from the first station during a particular period of time, control means mounted on said movable carriage for effecting the operation of said switching means, connecting means for establishing an electrical connection between said control means and said switching means only when the carriage is in its return position, and

operating means for operating said control means to effect the operation of said switching means when said electrical connection has been established.

25. A communication system including in combination a first teletypewriter station having a teletypewriterequipped with a plurality of pullbars and a movable carriage for carrying the pullbars, means for selectively operating the pullbars individually, means for moving said carriage along a fixed path of travel, a control contact mounted on said movable carriage, a plurality of other teletypewriter stations each provided with a teletypewriter; means for transmitting signals from the first station to the other stations, switching means at the first station mounted other than on said movable carriage for determining whether a teletypewriter located at one of the other stations shall record signals transmitted from the first station during a particular period of time, a slip connector finger mounted on a fixedly located portion of the teletypewriter at the first station, another slip connector finger mounted on said movable carriage, means for bringing said slip connector fingers into mutual engagement for completing an electrical connection between said control contact and said switching means, and operating means for operating the control contact in response to the operation of a preassigned pullbar for efiecting the operation of said switching means after said electrical connection has been completed.

26. A communication system including in combination a first teletypewriter station having a teletypewriter equipped with a plurality of pullbars and a movable carriage for carrying the pullbars, means for selectively operating the pullbars individually, means for moving said carriage along a fixed path of travel, said carriage having a return position, a control contact mounted on said movable carriage, a plurality 01. other teletypewriter stations each provided with a teletypewriter, means for transmitting signals from the first station to the other stations, switching means at the first station mounted other than on said movable carriage for determining whether a teletypewriter at one 01. the other stations shall record signals transmitted from the first station during a particular period of time, a slip connector finger mounted ona fixedly located portion of the teletypewriter at the first station, another slip connector finger mounted on said movable carriage, means for bringing said slip connector fingers into mutual engagement for completing an electrical connection between said control contact and said switching means only when said carriage is in its return position, and operating means for operating the control contact in response to the operation of a preassigned pullbar for efiecting the operation of said switching means when said electrical connection has been completed.

27. A communication system comprising in combination a transmitting station provided with a teletypewriter and a transmitter-distributor, operating means for operating the transmitterdistributor, said teletypewriter having a movable carriage, means for moving said carriage along a fixed path of travel, said carriage having a return position, a plurality of other teletypewriter stations each provided with a teletypewriter, means for enabling said transmitter-distributor to transmitsignals to the other teletypewriter stations, control means mounted on said movable carriage for effecting a selection as 

